Richard Ward said the London market had put in place a contingency plan to switch euro underwriting to multi-currency settlement if Greece abandoned the euro.

In an interview with The Sunday Telegraph he also revealed that Lloyd’s could have to take writedowns on its £58.9bn investment portfolio if the eurozone collapses.

Europe accounts for 18pc of Lloyd’s £23.5bn of gross written premiums, mostly in France, Germany, Spain and Italy. The market also has a fledgling operation in Poland.

Lloyd’s move comes as a major Franco-German provider of credit insurance for eurozone trade, Euler Hermes, said it was considering reducing cover for trade with Greece because of the risk the country might leave the eurozone.